JPH05313393A - Dielectric drum and its production as well as electrostatic recording device constituted by using the dielectric drum - Google Patents

Abstract

PURPOSE:To provide the dielectric drum which is reduced in the cost of production and with which a composite dielectric layer formed by coating the surface of an anodized film with an inorg. film and has uniform dielectric characteristics is easily obtainable while the pressure resistance is well maintained and the process for production of such dielectric drum and to provide the electrostatic recording device which is constituted by using this dielectric drum, is inexpensive and has high image reliability. CONSTITUTION:This dielectric drum is provided with the composite dielectric layer 2 formed by coating the surface of the anodized film 2a formed on the surface of an aluminum base plate 1 with the inorg. film 2b. An aluminum alloy pipe 3 of an aluminum alloy JIS 5000 type which is drawn and is subjected to a hardening treatment M is used as the above-mentioned aluminum base plate 1. This electrostatic recording device of a pressure transfer or pressure transfer fixing system is constituted by using such dielectric drum.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dielectric drum, a method for manufacturing the same, and an electrostatic recording apparatus using the dielectric drum, and more particularly, the surface of an anodized film formed on the surface of an aluminum substrate is an inorganic film. The present invention relates to a dielectric drum provided with a composite dielectric layer coated with, a method of manufacturing the dielectric drum, and an electrostatic recording device using the dielectric drum.

[0002]

2. Description of the Related Art As a conventional electrostatic recording device, for example, one described in Japanese Patent Publication No. 60-50083 is known. This is because an electrostatic latent image corresponding to an image signal is appropriately formed on the dielectric drum by the latent image forming device, and the electrostatic latent image on the dielectric drum is made visible by the toner of the developing device. The toner image on the drum is pressure-transferred or pressure-transfer-fixed onto the transfer medium by using a pressure roll.

As a dielectric drum used in such an electrostatic recording apparatus, not only the material weight is light in order to satisfy the demand for weight reduction of the apparatus but also during the transfer process by pressure or the transfer fixing process. In addition to the hardness and tensile strength required to withstand the mechanical stress of, the transfer process by pressure or the transfer fixing process
The hardness is required so that the dent phenomenon on the surface of the dielectric drum due to the wrinkling of the recording paper can be avoided. The dent phenomenon referred to here is a phenomenon in which a high pressure point is locally generated on the surface of the dielectric drum due to the occurrence of wrinkles on the recording paper, and the portion corresponding to the paper wrinkles on the surface of the dielectric drum is dented. The dents cause transfer defects, cleaning defects, and the like to cause image quality defects, and also shorten the drum life.

Therefore, in the past, aluminum alloy JIS 6000 series or 700 was used as the dielectric drum.
An aluminum substrate made of a 0-series aluminum alloy pipe is anodized on its surface to form a dielectric layer of an anodized film on the surface of the aluminum substrate. In such a dielectric drum, a sealing treatment is usually performed on the anodized film with an organic material such as wax or resin. In that case, an incomplete portion of the sealing is generated and the sealing material It has been found that the moisture absorption reduces the film resistivity in a high-humidity environment, lowers the function as a dielectric, and causes image deterioration. As a means for solving such a technical problem, the present applicant has already provided a dielectric drum in which the surface of an anodized film formed on the surface of an aluminum substrate is covered with an inorganic film (Japanese Patent Laid-Open No. 63-63). -58707).

[0005]

However, the hardness,
JIS 6000 series or 7000 series aluminum alloys with high tensile strength (especially, 7000 series aluminum alloys are called cemented carbides) are not easy to extrude and form pipes, and the processing cost is inherently high. Even if impurity control is performed on the aluminum alloy of (for example, homogenization treatment by heating performed in the billet state before extrusion molding of pipe), since there are many impurity species that do not dissolve, subsurface voids of the anodized film, A large number of surface pits appear, which causes a technical problem that the film characteristics deteriorate.

Further, in such a dielectric drum, in order to maintain the image transferability, cleaning property, etc. accompanying the uniformization of the dielectric characteristics, the surface roughness of the dielectric drum (here, the maximum height [JIS ]: It is necessary to finalize the maximum amplitude in the standard length) to, for example, 0.5 S (maximum height 0.5 μm) or less. However, JIS 6000 series or 7000 series aluminum alloys having high hardness and tensile strength generally contain many impurity (metal) species and the surface roughness becomes rough due to anodizing treatment, so that the surface roughness of the dielectric drum falls within the allowable range. In order to store it, it is necessary to perform a predetermined surface finishing treatment (polishing treatment) after the anodizing treatment. At this time, since the anodic oxide coating has a surface hardness about 5 times that of the aluminum alloy, it takes time to finish the surface after the anodic oxidation treatment, and it is extremely troublesome to obtain an anodic oxide coating with uniform dielectric properties. Met.

That is, as a substrate of a dielectric drum provided with a dielectric layer of an anodized film, JIS 6000 series or 70
When a 00 series aluminum alloy is used, there is a technical problem that the manufacturing cost of the dielectric drum is high and it is difficult to obtain an anodized film having uniform dielectric characteristics. The electric recording device inevitably becomes expensive, and the reliability of the dielectric characteristics of the dielectric drum may be reduced.

The present invention has been made in order to solve the above technical problems, and aims to reduce the manufacturing cost while maintaining a good pressure resistance, and to provide an inorganic film on the surface of the anodic oxide film. (EN) Provided are a dielectric drum capable of easily obtaining a coated composite dielectric layer having a uniform dielectric property and a manufacturing method thereof, and at the same time, an inexpensive electrostatic recording with high image quality reliability using the dielectric drum. A device is provided.

[0009]

That is, the present invention is
As shown in FIG. 1, a dielectric drum having a composite dielectric layer 2 in which the surface of an anodized film 2a formed on the surface of an aluminum substrate 1 is covered with an inorganic film 2b, is used as the aluminum substrate 1. Alloy JIS500
It is characterized in that the 0-system aluminum alloy pipe 3 is drawn and hardened M is used.

The invention relating to the above-mentioned method for manufacturing a dielectric drum is directed to an aluminum substrate manufacturing step of drawing and hardening treatment M of an aluminum alloy JIS5000 series aluminum alloy pipe 3, and a polishing step of polishing the surface of the aluminum substrate). An anodized film forming step of forming an anodized film 2a on the surface of the aluminum substrate 1 after this polishing step, and an inorganic film coating step of coating the surface of the anodized film 2a with an inorganic film 2b without polishing are performed. It is characterized by having.

Further, if the above-mentioned dielectric drum is used, the above-mentioned dielectric drum D and the toner image forming means 4 for forming a toner image on the dielectric drum D,
An electrostatic recording apparatus is provided as an invention, which is provided with a pressing unit 5 for transferring or fixing the toner image on the dielectric drum D onto a transfer target member 6 under pressure.

In such technical means, JIS 5000 series aluminum alloys used as the aluminum substrate 1 are JIS symbols A5052 and A515.
4, Al-M such as A5454, A5056, A5083, etc.
g-alloy is used.

As the pull-out hardening treatment M, generally, the tempering is performed by cold working, and the treatment indicated by H in the JIS classification code is applied. At this time, in order to increase the reliability of the dielectric properties, it is preferable to perform a stabilizing process such as a heat treatment for removing the strain of the aluminum alloy pipe 3 that may occur during the drawing hardening process.

Further, the degree of work hardening of the aluminum alloy pipe 3 may be appropriately selected according to the purpose of use of the dielectric drum, but when it is used as an electrostatic recording device, it is used during pressure transfer or pressure transfer. Hardness that can withstand mechanical stress at the time of fixing, not only having a tensile strength, it is necessary to have a hardness to the extent that dents are not generated due to the occurrence of paper wrinkles during pressure transfer or pressure transfer fixing described above,
When constructing an electrostatic recording device, the Vickers hardness of the surface hardness of the aluminum alloy pipe 3 must be harder than the hardness of the pressurizing means 5 such as a pressure roll. For example, a polyacetal pressure roll as the current pressurizing means. Considering the above, it is preferable to work-harden up to about HV 100 or more.

The present invention is intended for both those which perform the sealing treatment on the anodic oxide coating 2a and those which do not perform the sealing treatment. However, if the sealing treatment is performed, the pores of the anodic oxide coating 2a are filled and smoothed. By doing so, it is possible to further enhance the overall moisture-proof effect. In addition, fats and oils and synthetic resins are used as the organic sealing material. For example, as fats and oils, oleic acid, stearic acid, metal salts of these fatty acids, wax, lanolin, etc. are used,
As the synthetic resin, silicone resin, fluorine resin, epoxy resin, acrylic resin or the like is used. The sealing process is
When the organic sealing agent is an oil or fat, it is heated or dissolved in a solvent and immersed or applied. When the organic sealing agent is a synthetic resin, it is applied by spray dipping or the like. It is desirable that the excess organic sealing material applied to the surface of the anodic oxide coating 2a is appropriately scraped off by a scraper or scraped off by polishing with a grindstone. This is because if the sealing material remains in the pores of the anodic oxide coating 2a, the above-mentioned purpose of sealing can be achieved.

The inorganic film 2b coated on the anodic oxide film 2a is made of silicon nitride (Si ₃ N ₄ ), silicon oxide (SiO ₂ ), silicon carbide (SiC), aluminum nitride (AlN). , Alumina (Al ₂ O ₃ ), zirconia (Z
rO ₂ ) and insulating carbon (C). As a method of depositing the inorganic film 2b, CVD is used.
(Chemical vapor deposition: chemical vapor deposition)
Method, vacuum deposition method using heating or electron beam, various methods such as sputtering in which an inert gas ion is made to collide with a target, firing of a printed material, and the like. In order to secure the temperature, the temperature of the anodic oxide film during the process is 200 to 30 in each case.
It must be higher than 0 ° C. Therefore, in general,
A film containing oils and fats or synthetic resins that softens or melts at 200 ° C or higher may have a low binding strength of the inorganic film or may not be able to obtain smoothness of the film surface. In such a case, a film forming method is used in which the organic sealing material is not softened and melted and the thin film has high binding strength. An ion plating method is preferably used as such a film deposition method, whereby the inorganic film 2b can be conveniently formed. Of course, a method other than the ion plating method can be used as long as it can be maintained at a temperature equal to or lower than the melting point of the organic sealing material.

Further, in the electrostatic recording apparatus, if the toner image forming means 4 forms a toner image on the dielectric drum D, an electrostatic latent image by ions is written on the dielectric drum D. After that, the toner of the developing means is used to visualize the electrostatic latent image, or an electrostatic latent image is written by ion on the toner layer on the surface of the developing roll, and this is transferred onto the dielectric drum D. The design can be changed as appropriate, for example. The pressing means 5 may be appropriately selected as long as it can transfer or transfer-fix the toner image on the dielectric drum D to the transferred member 6 by pressing, but the transfer member 6 is conveyed. In consideration of the properties, roll-shaped ones are preferable. Further, when the transfer target member 6 is not present, since it contacts the dielectric drum D,
Hardness is lower than that of the dielectric drum D, or good toner releasability is required so that even if toner is accidentally attached, it is required to have good toner releasability. At present, engineering plastics such as polyacetal are used. ing.

The applicant of the present invention has already provided "a dielectric drum using a JIS 5000 series aluminum substrate and an electrostatic recording apparatus using the same" in cooperation with Nippon Light Metal Co., Ltd. Japanese Patent Laid-Open No. 3-294788) discloses that a single dielectric layer made of an anodized film is provided on the surface of a JIS 5000 series aluminum substrate.
This is clearly distinguished from the present invention in which a composite dielectric layer composed of an anodized film and an inorganic film is provided on the surface of a 5000 series aluminum substrate, in terms of purpose, constitution and effect.

[0019]

According to the technical means as described above, JIS5
000 series aluminum alloy pipe 3 is JIS6000
Since it is a material with a lower hardness than that of aluminum alloys of the 7000 series or 7000 series, extrusion molding of aluminum alloy pipes can be easily performed, and the surface roughness after anodizing can be suppressed to a low level. Processing becomes easy.

Further, the surface of the aluminum substrate 1 on which the JIS 5000 series aluminum alloy pipe 3 has been drawn and hardened is subjected to anodizing treatment.
Since the amount of impurity species is smaller than that of the Al-based or 7000-based aluminum alloy, the difference in the surface roughness of the anodized film 2a before and after the treatment is small, and the impurity species other than magnesium (Mg: dissolved in a solution) (for example, Since the amount of silicon described below is small, the appearance of subsurface voids and surface pits in the anodized film 2a is reduced. Here, when more specifically analyzing the change in the surface roughness of the anodized film before and after the anodizing treatment,
For example, a JIS6000 series aluminum alloy contains silicon (Si) as an alloy species, and this silicon remains in the anodized film without being anodized, which interferes with aluminum oxidation and causes a dent on the film surface. In addition, since silicon has a low solubility in aluminum and tends to gather near the surface layer (interface) of the drum when the pipe is formed, the silicon content rate of the surface layer portion becomes high, which affects the surface roughness. In contrast, JIS500
The 0-based aluminum alloy is a magnesium (Mg) -based alloy, and magnesium dissolves during oxidative dissolution, does not hinder the oxidation of aluminum, and has a high solubility in aluminum, and is uniformly dispersed. Therefore, it is considered that the change in surface roughness is small.

Furthermore, by using a relatively simple drawing-hardening treatment M, the pressure resistance of the JIS 5000 series aluminum alloy pipe 3 is sufficiently enhanced, and the hardness and tensile strength required for the aluminum substrate 1 of the dielectric drum are obtained. ..

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail based on the embodiments shown in the accompanying drawings. FIG. 2 shows an embodiment of an electrostatic recording device to which the present invention is applied. In the figure, reference numeral 20
Is a dielectric drum, 21 is an ion flow recording head for writing an electrostatic latent image by irradiation ions on the dielectric drum 20 in response to an image signal G from an image signal generator 22, and 23 is a static drum on the dielectric drum 20. A developing device 24 for developing the toner of the electrostatic latent image is arranged in pressure contact with the transfer portion of the dielectric drum 20, and at the same time as transferring the toner image on the dielectric drum 20 to the recording paper 26 conveyed by the paper conveying roll 25. A pressure roll for fixing (the pressure applied to the recording paper 26 in this embodiment is about 17
0 kg / cm ² ), 27 is a cleaner such as a cleaning blade that scrapes off and removes toner and paper dust slightly remaining on the dielectric drum 20 after the transfer and fixing step, and 28 is on the dielectric drum 20 after the transfer and fixing step. A static eliminator such as a scorotron that removes residual charges, and 29 is the recording paper 2 after the transfer and fixing process.
6 is a strip finger for peeling 6 from the dielectric drum 20 and the pressure roll 24.

The dielectric drum 20 used in this embodiment is manufactured as shown in FIG. That is, in this embodiment, first, an A5056 aluminum alloy ingot, which is one of JIS 5000 series aluminum alloys, is extruded by a pipe (step a) to manufacture an aluminum alloy pipe having a predetermined size.

Next, the aluminum alloy pipe is subjected to JIS quality code H38, specifically, the aluminum alloy pipe is subjected to a drawing-hardening treatment (step b) and then a stabilization treatment by low temperature heating ( Process c:
This is performed at 200 to 300 ° C. for 0.5 to 2 hours), and in this example, work hardening is performed until the surface hardness of the aluminum alloy pipe is about HV100 in Vickers hardness.

Further, the surface of the aluminum substrate made of the aluminum alloy pipe which has been subjected to the drawing-hardening treatment and the stabilizing treatment is polished to a surface roughness of 0.4 S (step d).
After that, a predetermined anodizing treatment (for example, JP-A-63-2945) is performed.
No. 86 publication) (step e) to form an anodized film on the surface of the aluminum substrate.

Thereafter, the inorganic film is not subjected to a sealing treatment on the anodic oxide film, and the anodic oxide film on the surface of the aluminum substrate is not particularly polished as shown in, for example, JP-A-63-58707. Nitride as ( _Si
N _x ) (step f) to cover the dielectric drum 20 described above.
Got

Next, when the change in the surface roughness of the dielectric drum used in this example before and after the anodizing treatment was examined, the results shown in Table 1 below were obtained.

[0028]

[Table 1]

According to Table 1, the surface roughness of the dielectric drum according to the example after anodizing was 0.5 S, which was almost the same as the surface roughness before anodizing of 0.4 S. On the other hand, a JIS A6061-T6 aluminum alloy pipe was ground to a surface roughness of 0.4 S and anodized by the same method as in Example 1 to make Comparative Example 1 whose surface roughness was measured. The value was 9S, which was almost twice the value before the treatment. Comparing the two, the surface roughness after the anodizing treatment of the dielectric drum 20 according to the example is almost the same as that before the treatment, so that the surface treatment before the inorganic film coating is almost unnecessary as compared with the comparative example 1. Be understood.

Further, using the electrostatic recording apparatus according to this embodiment, a paper wrinkle trouble test, that is, a crease of about 1 mm is previously made on the recording paper 26, and the recording paper 26 is loaded into the paper feeding device, When a test for checking the presence or absence of dents in the dielectric drum 20 was carried out by artificially causing paper wrinkles with a load of about 700 kg, the results shown in Table 2 below were obtained.

[0031]

[Table 2]

According to Table 2, no dent was found in the dielectric drum 20 according to the embodiment, and a printing experiment was conducted.
A good image could be obtained. In addition, in order to confirm the superiority of the electrostatic recording apparatus according to the embodiment, JISA5056
Comparative Example 2 is a dielectric drum in which an aluminum alloy pipe is anodized in the same manner as in Comparative Example 1 without being subjected to a pull-out hardening treatment, and an inorganic film coating treatment similar to that in Example is performed. When a paper wrinkle trouble test similar to that of the example was conducted with the electrostatic recording apparatus, the drum dent was found in the portion corresponding to the paper wrinkle by one test as shown in Table 2, and the result of the printing test was It was confirmed that the image quality was impaired.

In the examples, the one in which the anodic oxide film is not subjected to the sealing treatment is given as an example, but of course, the anodic oxide coating is subjected to the sealing treatment and then the inorganic film coating treatment is performed. There is no problem even if you do. In this case, the following effect differences will occur depending on the presence or absence of the sealing treatment. That is, when the anodic oxide film is directly covered with the inorganic film without resin sealing, the anodic oxide film substrate temperature can be raised to about 300 ° C. because the resin is not sealed. Accordingly, when the inorganic film is deposited, the selection range of the film deposition method is widened, and the hardness of the deposited inorganic film is increased. That is, various hard inorganic materials can be deposited without being restricted by the film deposition method. On the other hand, when the anodic oxide film is resin-sealed and then covered with an inorganic film, the substrate cannot be heated to a temperature higher than the heat-resistant temperature of the sealing resin, and therefore, for example, an ion plating method or the like must be used. Although the method of depositing the inorganic film will not be limited, even if minute defects during the deposition of the inorganic film or scratches over time occur, the underlying anodic oxide film layer is sealed. There is no concern that the electric resistance of the scratched portion will decrease, and the dielectric characteristics are unlikely to change accordingly.

[0034]

As described above, according to the first aspect of the present invention, as the aluminum substrate of the dielectric drum, a JIS 5000 series aluminum alloy pipe which is drawn and hardened is used. It is possible to provide a dielectric drum having high properties, uniform dielectric characteristics, and pressure resistance. That is, JIS60
Compared with the case of using a 00 series or 7000 series aluminum alloy pipe, extrusion molding of the aluminum alloy pipe can be easily performed, and the surface roughness after anodizing treatment can be suppressed to a low level. Since the process becomes easy, the manufacturability of the dielectric drum can be improved. In addition, the appearance of subsurface voids and surface pits in the anodized film can be suppressed, and the surface roughness after anodization can be suppressed to a low level, so the dielectric properties are uniform and the dielectric properties are maintained even in a high humidity environment. It is possible to easily obtain a composite dielectric layer of an anodized film and an inorganic film, which is excellent in environmental stability without deterioration of characteristics. In addition, the hardness and tensile strength of JIS 5000 series aluminum alloy pipes, which are originally low in hardness and tensile strength, are increased by a relatively simple drawing-hardening treatment, so that transfer or transfer fixing by pressure can be performed without impairing manufacturability. The pressure resistance can be easily obtained.

According to the second aspect of the present invention, attention is paid to the characteristics of the aluminum alloy JIS 5000 series, and the coating of the inorganic film is performed without performing the polishing treatment after the anodizing treatment.
It is possible to omit the polishing step for suppressing the surface roughness required when manufacturing the 0-system or 7000-system dielectric drum, and the manufacturing process of the dielectric drum can be simplified accordingly.

Further, according to the third aspect of the invention, since the dielectric drum having high manufacturability, uniform dielectric characteristics, and pressure resistance is used, the cost is low and the image reliability is excellent. An electrostatic recording device can be provided.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a configuration of a dielectric drum according to the present invention and an electrostatic recording apparatus using the dielectric drum.

FIG. 2 is an explanatory diagram showing an embodiment of an electrostatic recording device to which the invention is applied.

FIG. 3 is an explanatory diagram showing a manufacturing process of the dielectric drum used in the examples.

[Explanation of symbols]

D ... Dielectric drum, 1 ... Aluminum substrate, 2 ... Dielectric layer, 2a ... Anodized film, 2b ... Inorganic film, 3 ... JIS
5000 series aluminum alloy pipe, 4 ... toner image forming means, 5 ... pressurizing means, 6 ... transferred member

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Masaru Ogasawara 2274 Hongo, Ebina City, Kanagawa Prefecture Fuji Xerox Co., Ltd.Ebina Business Office (72) Inventor Akimasa Komura 2274, Hongo, Ebina City, Kanagawa Prefecture Fuji Xerox Co., Ltd.Ebina Business In-house (72) Inventor Gouji Nagao 2274 Hongo, Ebina-shi, Kanagawa Fuji Xerox Co., Ltd.

Claims (3)

[Claims] 1. A dielectric drum provided with a composite dielectric layer (2) in which the surface of an anodized film (2a) formed on the surface of an aluminum substrate (1) is covered with an inorganic film (2b). A dielectric drum, wherein an aluminum alloy JIS 5000 series aluminum alloy pipe (3) obtained by drawing and hardening (M) is used as the aluminum substrate (1). 2. An aluminum substrate manufacturing process of drawing and hardening (M) an aluminum alloy JIS 5000 series aluminum alloy pipe (3), a polishing process of polishing the surface of the aluminum substrate (1), and this polishing process completed. Anodized film forming step of forming an anodized film (2a) on the surface of an aluminum substrate (1), and an inorganic film coating step of coating the surface of this anodized film (2a) with an inorganic film (2b) without polishing A method for manufacturing a dielectric drum, comprising: 3. A dielectric drum (D) according to claim 1,
Toner image forming means (4) for forming a toner image on the dielectric drum (D) and pressure transfer or pressure transfer fixing of the toner image on the dielectric drum (D) onto a transfer target member (6). An electrostatic recording device, comprising: